A Study of LY4355756 in Healthy Participants

NCT07765498 | Not Yet Recruiting Phase 1 FDA Drug

• 2 other identifiers: 27803J6U-MC-KZAA
• Study Type: interventional
• Target: 123
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of the study is to assess how LY4355756 is absorbed by the body and how safe it is to healthy participants. There will be four inpatient stays at the clinical research unit (CRU). For Part A there will be 5 continuous days, Part B 22 continuous days, Part C 5 continuous days in each of the 3 periods, and Part D 18 continuous days in the CRU.

Conditions

Healthy

Outcome Measures

Primary Outcomes (2)

• Number of Participants with One or More Serious Adverse Event(s) (SAEs) Considered by the Investigator to be Related to Study Drug Administration

  Baseline up to the Safety Follow up Visit (6 months)

• Number of Participants with One or More Treatment-Emergent Adverse Event(s) (TEAEs) Considered by the Investigator to be Related to Study Drug Administration

  Baseline up to the Safety Follow up Visit (6 months)

Secondary Outcomes (4)

• Pharmacokinetics (PK): Area Under the Curve (AUC) of LY4355756

  Baseline up to Day 18

• PK: Maximum Plasma Concentration (Cmax) of LY4355756

  Baseline up to Day 18

• PK: AUC of Midazolam

  Baseline up to Day 14

• PK: Cmax of Midazolam

  Baseline up to Day 14

Study Arms (5)

LY4355756 Part A

EXPERIMENTAL

Single-ascending dose (SAD) of LY4355756 administered orally

Drug: LY4355756

LY4355756 Part B

EXPERIMENTAL

Multiple-ascending doses (MAD) of LY4355756 administered orally

Drug: LY4355756

LY4355756 Part C

EXPERIMENTAL

Single dose of LY4355756 administered orally in each of three study periods

Drug: LY4355756

LY4355756 + Midazolam Part D

EXPERIMENTAL

LY4355756 and midazolam co-administered orally

Drug: LY4355756; Drug: Midazolam

Midazolam Part D

EXPERIMENTAL

Midazolam administered orally

Drug: Midazolam

Interventions

LY4355756 DRUG

Administered orally as capsule

LY4355756 + Midazolam Part D; LY4355756 Part A; LY4355756 Part B; LY4355756 Part C

Midazolam DRUG

Administered orally as liquid

LY4355756 + Midazolam Part D; Midazolam Part D

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Are overtly healthy as determined by medical evaluation, including medical history, physical examination, laboratory tests, electrocardiogram (ECGs), and vital signs
• Have a body mass index within the range 18.0-32.0 kilograms per square meter (kg/m²) (inclusive)
• Individuals assigned male at birth (AMAB) or assigned female at birth (AFAB)
• Contraceptive use by participants should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies

You may not qualify if:

• Have presence of significant uncontrolled respiratory, cerebrocardiovascular, cardiovascular, hepatic, renal, gastrointestinal, endocrine, hematologic, neurologic, or psychiatric disorders, or abnormal laboratory values at screening
• Have an abnormality in 12-lead ECG at screening that, in the opinion of the investigator, may increase the risk associated with participating in the study or may confound ECG data analysis
• Have a diagnosis or history of malignancy within 5 years prior to screening
• Exceptions:
• basal cell or squamous epithelial carcinomas of the skin that have been resected with no evidence of metastatic disease for 3 years
• cervical carcinoma in situ, with no evidence of recurrence within the 5 years prior to screening
• Have had breast cancer within the past 10 years
• Have a history or presence of multiple or severe allergies, or an anaphylactic reaction, to prescription or nonprescription drugs or food
• Have a current or recent acute, active infection. For at least 30 days before screening and up to the randomization visit, participants must have no symptoms or signs of confirmed or suspected infection and must have completed any appropriate anti-infective treatment
• Have a current infection with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV)
• Have received any live (including attenuated live vaccines), non-live, or inactivated vaccine(s) within less than 4 weeks before randomization or intend to receive them during the study
• Are individuals AFAB who, during the study, are pregnant, have positive pregnancy testing, intend to become pregnant, are lactating, or intend to breastfeed

Sponsors & Collaborators

• Eli Lilly and Company: lead

Study Sites (1)

Fortrea Clinical Research Unit

Dallas, Texas, 75247, United States

Location

MeSH Terms

Interventions

Midazolam

Intervention Hierarchy (Ancestors)

Benzodiazepines; Benzazepines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds

Study Officials

• Call 1-877-CTLILLY (1-877-285-4559) or 1-317-615-4559 Mon - Fri 8 AM - 8 PM Eastern time (UTC/GMT - 5 hours, EST)

  Eli Lilly and Company

  STUDY DIRECTOR

Central Study Contacts

Trial questions or participation questions: 1-877-CTLILLY (1-877-285-4559) or

CONTACT

1-317-615-4559; LillyTrials@Lilly.com

Physicians interested in becoming principal investigators please contact

CONTACT

clinical_inquiry_hub@lilly.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Parts A and B are Double-Blinded, Parts C and D are Open-Label
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Parts A and B are parallel; Part C is crossover; Part D is sequential

Study Record Dates

• First Submitted: August 11, 2026
• First Posted: August 14, 2026
• Study Start: August 1, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 1, 2027
• Last Updated: August 14, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)